<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Title</title>
</head>
<body>

</body>
<script>
	class Box{
		constructor() {
			this._userName = "lala"
		}
		get userName(){
			return "《"+this._userName+"》";
		}
		set userName(v){
			this._userName = v;
		}
	}
	const obj = new Box();
	obj.userName = "xixi";
	console.log(obj.userName)
</script>
</html>